The present invention relates to an improved intake manifold, throttle, and injector structure for a multi-cylinder internal combustion engine of the so-called single injection point type.
It is well known to provide air/fuel mixture for an internal combustion engine by a single fuel injection valve which injects fuel into the intake manifold to be supplied to all the cylinders. Such an engine is commonly referred to as a single injection point type engine. The injection valve is mounted in the intake manifold at a point upstream of where it branches into individual pipes to serve the individual cylinders. Because of the varying characteristics of each of these individual pipes, they are individually sized so as to enable the engine to develop its maximum output power.
Accordingly, it is very difficult to make the best use of the inertia supercharging effect over the whole range of engine operational conditions. In the low load range, particularly, the air flow speed in the manifold is low, and the fuel is therefore not atomized properly. Thus so-called "wall flow" may occur; that is, droplets of fuel may collect on the wall of inlet the manifold. This may lead to slow engine response.